1. Field of the Invention
The present invention relates generally to Global Positioning System (GPS) receivers, and in particular, to a method and apparatus for a weighted dilution of precision calculation for GPS fix qualification.
2. Description of the Related Art
The use of Satellite Positioning System (SPS) signals, typically realized in GPS receivers, in consumer products has become commonplace. Hand-held devices used for mountaineering, automobile navigation systems, and GPS for use with cellular telephones are just a few examples of consumer products using GPS technology.
GPS-enabled devices, such as cellular telephones, have also been introduced into the consumer marketplace. These devices allow for the use of Location-Based Services (LBS) which are services, advertisements, and other features that are offered based on the location of the user. As such, GPS-enabled devices are used worldwide.
As GPS technology is being combined with these devices, the GPS chips are being placed in widely ranging applications. Initially, GPS chips were designed for surveying applications, and, as such, the chip and system design was engineered to provide highly accurate positioning measurements and data, without regard to power consumption, semiconductor chip footprint, or other conditions. The GPS chip design was optimized to deliver position data, rather than optimized for each environment the chip is being placed into. Further, some of the GPS portions are being made on the same semiconductor chip as other portions of the combined devices, which subject the GPS portions of these electronic devices to widely-varying semiconductor processing steps.
Since the GPS chips are now being placed into devices that are far afield from the initial intended use for GPS, it can be seen, then, that there is a need in the art to alter the design of a GPS chip to match the requirements of the intended end-user device and environment.